Potassium ion influx and Na+,K+-ATPase activity are required for the hamster sperm acrosome reaction

R. J. Mrsny, S. Meizel

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The role of a K+ ion influx and Na+,K+-ATPase activity in the hamster sperm acrosome reaction (AR) was examined, using a range of concentrations of K+,K+ ionophores and a Na+,K+-ATPase inhibitor. Washed epididymal hamster sperm, capacitated in vitro in an artificial medium containing 2 mM Ca2+, 147 mM Na+, and 3, 6, 12, 18, or 24 mM K+, began undergoing the AR after 3 h of incubation. Sperm incubated in low K+ (0.9 mM) failed to undergo the AR even after 5 h of incubation. Sperm in 0.9 mM K+ could be induced to undergo the AR when either K+ (12 mM) alone or K+ (12 mM) with 0.1 microM nigericin was added after 3.5 h of incubation. The addition of K+ alone stimulated the AR in 30 min, whereas nigericin plus K+ stimulated the AR 15 min after addition. Neither nigericin added alone (0.9 mM K+) nor nigericin plus 12 mM K+ added to a low Ca2+ (0.35 mM) system resulted in acrosome reactions. Valinomycin (1 nM) did not stimulate the AR when added together with K+ (3-24 mM) to sperm incubated in 0.9 mM K+ for 3.5 h but markedly decreased sperm motility. Micromolar levels of ouabain blocked the AR when added between t = 0--3 h to sperm incubated with 3-24 mM K+. Inhibition of AR by the addition of 1 microM ouabain to sperm incubated with 3 mM K+ was completely reversed by the addition of 0.1 microM nigericin at t = 3.5 h. These results suggest that Na+,K+-ATPase activity and the resulting K+ influx are important for the mammalian sperm AR. Some similarities between requirements for the hamster sperm AR and secretory granule exocytosis are discussed.

Original languageEnglish
Pages (from-to)77-82
Number of pages6
JournalJournal of Cell Biology
Issue number1
Publication statusPublished - 15 Oct 1981


  • Acrosome/physiology
  • Animals
  • Cricetinae
  • Exocytosis
  • Ionophores/pharmacology
  • Male
  • Mesocricetus
  • Nigericin/pharmacology
  • Ouabain/pharmacology
  • Potassium/physiology
  • Sodium-Potassium-Exchanging ATPase/metabolism
  • Sperm Motility/drug effects
  • Spermatozoa/enzymology

ASJC Scopus subject areas

  • Cell Biology


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